Film photography has been surpassed by digital photography, and with it, by the expedited death of less popular formats. Film, which has a chemical layer that reacts with the addition of light to record a negative image of the light it is exposed to, is typically loaded into a camera in a film chamber, wrapped around a spool. It is pulled off the spool and onto a take-up spool on the other side of a shutter. A portion of the unrolled film is exposed to light when a shutter opens, a lens focusing light onto the exposed film.
Many formats of film exist in various sizes, various chemical compositions used to form a negative image of light hitting it (or in some cases, a positive image), and come in color, black and white, infrared, and other varieties. Film formats change over time, and, with the prevalence of digital photography, the discontinuation of various film formats is accelerating. Thus, for example, a camera which takes 70 mm film is difficult to use, and manufacture of 116 and 616 film has long been discontinued. Likewise, 620 and 828 roll film is no longer produced by any major film processing company, and 127 film is on manufactured by a single company in Croatia at the time of this writing.
While the prior art has cameras which can hold multiple types of film, most are designed for a single-size film. For example, U.S. Pat. Nos. 2,565,618, 2,584,373, and 2,693,137 allow one to choose between a first roll of film and a second roll of film. While U.S. Pat. No. 5,515,124 discloses the ability to change an image format in a camera, this method, unfortunately, does not breathe new life into old cameras, but rather, new life into old film. A proprietary camera must be used.
Thus, there is a need to draw new life into old cameras, in order to extend their use by enthusiasts, artists, and posterity.
Referring now to FIG. 1, this figure shows the back of a typical camera as known in the prior art. A film chamber 19 holds film, such as 35 mm or 70 mm film (a 35 mm camera is shown in FIG. 1, by way of example). In the case of 70 mm film, reel sizes may be 116 or 616 reels which have different thicknesses. Shutter 20 opens and closes to allow light in, which has been focused by a lens (in most cases). The light exposes an unrolled portion of the film which has notches or sprocket holes adapted for engagement with sprocket teeth 22. In this manner, the film can be unrolled and pulled from the film chamber 19 to a take-up spool 23 by mechanically rotating the sprocket teeth 22. Film pressure plate 24 and the camera back cover 25 keep the film flat and unexposed to light when it is unrolled between the spools. Some cameras have a power winder coupler 26, allowing one to insert a tool with rotating head to wind the film quickly. In many cameras, an internal motor exists to accomplish this, and may be activated by a rewind button 27. Film rail 28 and film guide rail 29 further ensure that the film remains in its proper place, in order to ensure the precise positioning of negative pictures on the film and that the film does not get stuck. (If the film did get stuck, the camera would have to be opened under infrared, low intensity, or pitch black light conditions (depending on film type), in order to ensure that photographs on the film are not ruined by over-exposure to light). For purposes of this disclosure, a “film rail” is defined as a portion above a space for the shutter opening, or below a space for the shutter opening. An edge of film may rest on the film rail, may be engaged with sprockets on the film rail, or may pass between upper and lower film rails. Other features of typical cameras include tripod sockets 30 for mounting the camera on a tripod, a battery chamber 31 where the camera's battery is stored, and other buttons 32.